A typical summer's day in Los Angeles: temperatures nudge the nineties, the sun blazes high in the sky, palm trees sway in the ocean breeze, and sprinklers spray a fine mist of water into the scorching air.

But if the predictions of climatologists, environmentalists, city planners and the head of the water board are correct, the sprinklers and many other of the comforts that have made southern California habitable may have to be turned off.

Experts across the city concur that the conditions are ripe in southern California for the "perfect drought". Los Angeles has recorded just 8.15cm (3.21in ) of rain in the year ending June 30, making it the driest year on record since 1877. According to the National Drought Mitigation Centre, southern California faces "extreme drought" this year, with no rain forecast before September. One climatologist referred to the temperatures in Los Angeles as "Death Valley numbers".

The Sierra Nevada mountains, which typically provide Los Angeles with 50% of its water, have provided just 20% of their normal volume this year, and the snowpack is at its lowest for 20 years. Pumping from an aquifer in the San Fernando Valley was stopped this month because it was contaminated with chromium 6.

While the waters dry up, demand for the scarce resource increases. Not only has southern California seen a growth in its population of two-to-four times the national average in the past 50 years, but neighbouring states such as Nevada and Arizona are also experiencing population booms. And they all claim water from the same source, the Colorado River.

"I call it the dry incendiary summer of 2007," says Bill Patzert, a climatologist at NASA's Jet Propulsion Laboratory in Pasadena. "Mother nature is converging with human nature. With population growth and the decline in the water there are the elements in the equation which you could call the perfect drought."

Although southern California has experienced severe drought before, this time could be different. Climate change, some argue, means that the lack of rainfall and the elevated temperatures will become the norm. "Nature never intended to support this many people here," said David Nahai, president of the board of the city's water and power commissioners. "If we have two years like we have now then we will have to take some drastic measures. But we're not pushing the panic button."

Just what those drastic measures may entail will be familiar to those in more temperate climates, such as the UK: mandatory hosepipe bans, restrictions on car washing - a twice-weekly activity for many Angelenos - and planning measures to force developers to consider water use. "It's disgusting that Los Angeles parks and golf courses are being irrigated with potable water," says Nahai. "We have to re-educate people about living here."

Melanie Winter, of the LA-based River Project, says that land use and 20th century flood controls - LA's storm drains to channel the rain into the sea - need to be changed to make the city more self-sufficient and less dependent on water travelling hundreds of miles through pipelines and aqueducts.

"We spend $1bn to import water and $500,000 to throw local [rain] water into the ocean," she said. "In 30 years we may be able to provide 65% of our drinking water locally rather than 15%."

There may, however, be an upside, Patzert suggests. "The last 10 years we've had bumper grape harvests. Two buck Chuck [a local, palatable cheap plonk] is the result of global and regional heat-up."